Light weight cigarette filter



Ange 1 .1. F. CAINES ETAL. LIGHT WEIGHT CIGARETTE FILTER Original Filed Jan. 9, 1961 Cfi/MPED comm/0011s F/LME/VTS Q. (PRIOR ART) 2 C/G44/?E7 T5 PAPER 70.54660 WIMP TOH WCU C/P/MPED COIV 7' Iii/U 01/5 F/LMENTS (Smaller Angle offieiained Crimp) F/LTER WIMP C/GARET TE 8 TOBACCO JAMES lf/VOX P14A/A/"LL,JR

INVENTORS I'V. um/ 4 United States Patent 3,202,155 LIGHT WEEGHT CIGARETTE FILTER James F. Gaines, Richard F. Dyer, and .IamesKnox Panniil, Jan, Kingsport, Tenn, assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Continuation of application Ser. No. 81,593, Jan. 9, 1961. This application dune 5, 1964, Ser- No. 379,425 4 (Iiaims. (Cl. 131-49) This application is a continuation of our application Serial No. 81,593 filed January 9, 1961, now abandoned which in turn is a continuation-in-part of our earlier application Serial No. 27,091 filed May 5, 1960 now U-S- Patent No. 3,099,594.

This invention relates to tobacco smoke filters. More particularly this invention relates to a cigarette fil er rod of element which is of lighter weight than currently used rods but yet is as eificient or more efficient than presently used filters.

As is well known in the industry, a large number of small filter rods or elements are used in connection with tobacco products. For example, a large portion of the cigarettes produced domestically and abroad have filter tips which are usually at least one centimeter or more in length and of the diameter of the cigarette to which the tip is associated. While some of these filter tips or plugs are made from paper, cotton wadding or the like, a large number are made from crimped synthetic filaments. In any event, when it is considered published reports indicate that an excess of 60,000,000 pounds of filter material is consumed in filter manufacture domestically, it is readily apparent that reducing the weight of such filter rods is a highly desirable result particularly if this may be done without impairing the filtering efficiency of the rod. Such reduction in weight is not only useful in saving material cost, but gives other benefits such as lowering shipping costs which, in view of the highly competitive nature of the filter market, is of value. In other words, because of the rather small cost margins involved due to filter rods being a low priced item, it is apparent that such savings which may be accomplished by the present invention represents a highly desirable result.

After extended investigation we have discovered a filter rod and its method of manufacture, which rod is substantially lighter in weight than currently used filter rods but which rod is as efficient or more efiicient as respects tar removal and in other respects is equal 'to or better in efiiciency than currently used filter rods.

This invention has for one object to provide a filament filter rod.. Another object is to provide a filter element for cigarette filter purposes which is lighter in weight than comparable filters in commercial use but which filter tip cigarette comprised of the novel rod of the pres- Still a further object is to provide a new filter tip cigarette comprised of the novel rod of the present invention in association with smoking tobacco. A particu lar object is to provide a filter made of crimped synthetically spun filaments wherein the contraction due to the crimps is retained to a substantially greater extent than has been considered possible with current filter rod production methods. Another object is to provide a filter rod which is substantially harder than currently used filters. Still another object is to provide a method of making the new lighter weight filter rods of the type referred to above. Other objects will appear hereinafter.

In the broader aspects of our invention we have found that if the synthetically spun filaments which are to be made into tobacco smoke filter rods are subjected to a treatment which we refer to as cylindrical blooming, the resultant filter rods may be made with a definite weight advantage. This weight advantage may be at least 3% B,Z@Z,l55 Patented Aug". 24:, 1965 and in many instances the Weight advantage may be up to 15% or 20%. Such lighter weight filter rods of the present invention exhibit tar removal efiiciency, pressure drop characteristics and the like as good or better than currently produced filter rods. In addition, the new rods of the present invention are firmer than prior art rods and, therefore, are more adaptable to assembly in automatic machinery as well as supplying a firmer tip which many smokers may prefer.

In a filter rod, the contraction of the base fiber due to retained crimp may be equated and is generally referred to as the average angle of retained crimp (alpha). If no crimp were retained, the fibers would lie essentially parallel to the smoke flow path through the filter and (alpha) would approach 180. Since little fiber surface would then be oriented normal to the smoke flow path, filtration efiiciency, which depends upon impingement, would be low.

Our new filter has an average angle of retained crimp substantially smaller, and consequently a greater area of fiber surface presented to the smoke, than has been possiblein prior art rods made from filaments. Such reduction in the crimp angle is at least as great as 25 and -vantages amy be obtained therefrom such as increased firmness and the like. This may be accomplished by subjecting the crimped synthetically spun filaments to a treatment of cylindrical blooming which will. be described in detail hereinafter.

For assistance in a further understanding of our invention, reference is made to the attached drawing forming a part of the present application.

FIG. 1 is a side elevation view on a slightly enlarged scale and partly in section for showing a prior art filter.

FIG. 2 is likewise a side elevation view partly in section for illustrating 'the filter of the present invention wherein the contraction due to retained crimp is appreciably greater.

FIG. 3 is a diagrammatic side elevation view on a considerably enlarged scale of a crimped filament for illustrating the matter of angles as referred to above and as will be described in more detail hereinafter.

FIGS. 4 and 5 are also similar side elevation views on an exaggerated scale of a plurality of filaments for further illustrating the matter of crimp retention.

Referring to FIGURE 1 which concerns the prior art filter, 2 indicates the over-all cigarette to which the filter tip 3 is attached. This'filter tip or plug is wrapped with a usual filter wrap material such as paper as indicated at 4. The filter is made up of several thousand crimped continuous filaments generally indicated as at 5. However, it will be noted as are that although the contraction due to crimp may be discernible, such is not to the comparable extent as is the case in the present invention as will be discussed in connection with FIGURE 2.

Referring to FIGURE 2, in a comparable manner a cigarette is indicated at S. The filter wrap 9 may be the same as in FIGURE 1. However, the filter 1%) of the present invention, although it may be made of the same size and composition of crimped continuous filaments, the structure and arrangement of the filaments is different from that of FIGURE 1. For example, referring to a group of filaments at 11 it will be observed that the contraction due to retained crimp angle is very great. That is, in the present inventionit -is preferred that the average angle of retained crimp be at most Referring now to FIG. 3 the following formula may :be derived:

sine %alpha -52 Alpha=Angle of retained crimp Y Length equivalent to wt. of crimp-free tow 2X :Length equivalent to wt. of fiber contracted due to retained crimp For a rod L mm. long From this formula it will be observed that from a comparison of the weight of filter, a relationship respecting the amount of retained crimp may be ascertained.

From the foregoing and referring to FIGS. 4 and 5 it can be seen that where the angle is much above 100, as the 140 indicated in FIG. 4, the resultant filter will not be as good as that of FIG. 5 Where the angle i indicated as 90.

Further information concerning the new structure of the filter rod of the present invention and its method of manufacture will be had from the following description. A tow of a suitable nature for making filters would be obtained. This tow may bea tow such as currently used in filter manufacture. Or, the tow may be of certain types to be described below such as debundlized tow.

Quite useful tows are described in Crawford and Stevens U.S. Patents 2,794,239, 2,953,837, and 2,953,838. Such tows although of a compacted nature have useful yarn treating agents thereon and are preferably uniformly crimped to start with. While for a number of reasons we prefer a tow essentially comprised of crimped continuous cellulose acetate filaments, it is possible in the present invention to utilize filaments of other compositions such as regenerated cellulose, polyesters, polyamides, polyacrylics, and polyolefins and the like, as will be apparent from the description which follows and certain of the specific examples.

Another form of tow which may be used in the present invention is debundlized tow as described in companion Caines, Dyer and Pannill application Serial No. 27,091. In the event debundlized tow is employed, such tow may be substantially directly fed into the garniture of the filter rod forming mechanism as shown in Crawford and Stevens Patent 2,794,480 or as disclosed in Wexler companion application Serial No. 761,602.

the suitable cylindrical blooming for processing the tow to make the new filter rods of the present invention, the preferred gas pressure to utilize and the like information is generally in accordance with the following:

The tow is withdrawn from the package vertically through a banding device such as shown in Stevens Patent 2,908,045 and thence over a guide to the nip between a pair of feed rolls. The banded tow is passed then over a suitable plasticizer applicator, if a plasticizer is desired, and thence to the cylindrical blooming jet. In the jet the tow passes through a cylindrical entrance nozzle wi y inch in diameter whence it emerges in the path of a peripheral stream of high velocity air. The perferred air pressure used is 20-25 pounds per square inch, gage. The filaments of the tow are thoroughly debundlized in the throat of the cylindrical jet and in the subsequent divergent passage of the jet with a minimum of longitudinal extension. At the exit of the jet the debundlized tow is compacted in a chamber consisting of spring steel strips or other restricting means wherein a certain amount of crimp compaction is restored and a controlled withdraw-a1 rate is assured.

By the procedure just described, the contraction due to retained crimp is maintained at a much higher level than is possible with tension (mechanical blooming). Furthermore, even with tow having a high degree of crimp such cylindrical blooming does not cause breakage or other damage to the tow whereas prior art mechanical treatments are limited to some extent by the possibility of potential damage to the crimp or because of undue breaking.

After the tow has been cylindrically bloomed in a suitable rnanner, it is then withdrawn by means of a suitable roll and passes thence to a filter rod forming machine of the type generally used in the commercial production of filters and cigarettes. The tow is here wrapped in a suitable wrapper at a specified diameter and, after sealing, is cut into lengths suitable for use for assembly onto cigarettes.

A further understanding of our invention will be had from the consideration of the following examples which are set forth for illustrating certain improved embodi- Inents.

Example I Rods were produced by the tension blooming process as disclosed in US. Patent 2,794,480 (Crawford et al.) from 3 D./F., 84,600 TD. cellulose acetate tow. Using the cylindrical blooming process of the present invention, it was found that a 3 D./F., 53,000 T.D. resulted in rods of approximately the same pressure drop. Analyses of the rods are tabulated below.

Although there was considerable reduction in weight, the new filter of the present invention functioned as well as the older filter in all respects and in certain respects had better properties.

Example II As above, filter rods were made by the two processes,

using 5 D./F. cellulose acetate tows. The data are tabulated below.

Tension Cylindrical Process Process Rod pressure drop, in. of water.. 11.0 11.1 Hardness value 5. 2 3. 2 Wt. of acetate tow in rod, gms 1. 015 .787 Reduction in tow weight, percent l. 22. 5 Angle of retained crimp, degrees 160 Example HI As in Example I, filter rods were made by the two procsesame In the above examples, all rods were 24.8 mm. circumference by 90 mm. long. The hardness value is the rod compressionunder a specified load, measured in tenths of a millimeter. A low value is indicative of a firm rod.

Example IV Rods were produced by the cylindrical blooming proc ess without plasticizer using 3 D./F., 80,000 TD. viscose tow. Rod firmness was sufiicient for assembly although no filament bonding agent was used. The pressure drop and weight were comparable to those obtained with equivalent cellulose acetate tow.

Example V Filter rods produced from a 3.4 D./F., 50,000 T.D. polypropylene tow by the cylindrical blooming process had an average angleof retained crimp of 68. Tow debundlizing was satisfactory and the rod characteristics were somewhat comparable to those of conventional cellulose acetate rods although no plasticizer was used.

Example VI Filter rods were produced with the cylindrical blooming process using a highly randomized tow produced by the free-fall spinning method at very low spinning draft, in the order of 0.2, with a 4 D./F. tow of 33,000 T.D. which had an apparent total denier of 50,000 due to the random orientation of the filaments, filter rods of commercial firmness were produced by applying the plasticizer with a wick applicator to the outer surfaces of the tow and redistributing the plasticizer throughout the tow uniformly enough to provide the necessary bonding at filament intersections by passing the tow through the cylindrical blooming jet described in parent Caines at al. application referred to above.

It can be seen from the above examples that by the present invention it is possible to produce a filter rod which is considerably lighter in weight than prior art rods but which is efiicient and in some respects more. advantageous than the prior art rods. It can also 'beseen that filters may be produced from materials which cannot be plasticized, in the accepted sense of the term, but which have sufficient firmness for further processing.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. As a new article of manufacture a filter rod useful as a tobacco smoke filter comprised of a cylindrical bundle of at least 10,000 crimped continuous spun filaments V of a denier per filament below 8, said crimp being uniform and of the order of at least 9 crimps per inch, said crimped filaments extending the length of the rod and some of said filaments being adhered to adjacent filaments at zones of contact by plasticizer action, a wrapper around the periphery of said rod, said rod being characterized in that the aforesaid initial uniform crimp in the filaments has not been materiallydiminished during the cylindrical blooming step employed in making the rods whereby the average angle of retained crimp of each of said crimped filaments is sharp and is less than and the Weight of this new rod is at least 3% less than the weight of a tension bloomed prior art rod containing filaments of equal denier and having like length, circumference, pressure drop and tobacco smoke removal efficiency.

2. As a new article of manufacture a filter rod useful as a tobacco smoke filter comprised of a bundle of at least 10,000 crimped continuous spun filaments which have been cylindrically bloomed, said crimp being uniform and of the order of not less than 9 crimps per inch, said uniformly crimped filaments extending the length of the rod and being bonded to at least some of the adjacent filaments at zones of contact, a wrapper around the periphery of said rod, the extended length of the filaments in said new rod being longer than the extended length of the filaments in a prior art tension bloomed rod inasmuch as the filaments of said new rod have a sharp angle of retained crimp wherein the angle is less than 100", said new rod containing fewer of said uniformly crimped filaments than prior art rods, the combination of the filament length and number of filaments in said new rod providing a filter rod weighing at least 3% less than a tension bloomed prior art rod of equal length, circumference, firmness, pressure drop and smoke removal efiiciency,

3. The rod in accordance with claim 2 wherein the filaments are primarily comprised of cellulose acetate and the denier per filament is not greater than 8.

4. As a new article of manufacture a filter tip cigarette comprised of a cigarette having attached to one end thereof a tobacco smoke filter element, said. element being characterized in that it is an article of manufacture in accordance with claim 1.

References Cited by the Examiner UNITED STATES PATENTS 2,790,208 4/57 Smith 131--208 2,794,239 6/57 Crawford et al. 131208 3,023,075 2/62 Larman et al 131-208 3,025,130 3/62 White 131-208 ABRAHAM G. STONE, Primary Examiner, MELVIN D. REIN, Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,202, 155 August 24, 196.

James F. Caines et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 54, strike out "tip cigarette comprised of the novel rod of the pres" and insert instead is equal to or better in efficiency than currently Signed and sealed this 19th day of July 1966.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

1. AS A NEW ARTICLE OF MANUFACTURE A FILTER ROD USEFUL AS A TOBACCO SMOKE FILTER COMPRISED OF A CYLINDRICAL BUNDLE OF AT LEAST 10,000 CRIMPED CONTINUOUS SPUN FILAMENTS OF A DEINER PER FILAMENT BELOW 8, SAID CRIMP BEING UNIFORM AND OF THE ORDER OF AT LEAST 9 CROMPS PER INCH, SAID CRIMPED FILAMENTS EXTENDING THE LENGTH OF THE ROD AND SOME OF SAID FLAMENTS BEING ADHERED TO ADJACETN FILAMENTS AT ZONES OF CONTACT BY PLASTICIZER ACTION, A WRAPPER AROUND THE PERIPHERY OF SAID ROD, SAID ROD BEING CHARACTERIZED IN THAT THE AFORESAID INITIAL UNIFORM CRIMP IN THE FILAMENTS HAS NOT BEEN MATERIALLY DIMINISHED DURING THE CYLINDRICAL BLOOMING STEP EMPLOYED IN MAKING THE RODS WHEREBY THE AVERAGE ANGLE OF RETAINED CRIMP OF EACH OF SAID CRIMPED FILAMENTS IS SHARP AND IS LESS THAN 100* AND THE WEIGHT OF THIS NEW ROD IS AT LEAST 3% LESS THAN THE WEIGHT OF A TENSION BLOOMED PRIOR ART ROD CONTAINING FILAMENTS OF EQUAL DENIER AND HAVING LIKE LENGTH, CIRCUMFERENCE, PRESSURE DROP AND TOBACCO SMOKE REMOVAL EFFICIENCY. 